# CVE-2026-57192: Asterisk: Out-of-Bounds Write in Codec2 Decoder Due to Floor/Ceil Sample Count Mismatch

Status: published. Published: 2026-10-27. Updated: 2026-11-03.

Asterisk is an open source private branch exchange and telephony toolkit. Prior to Asterisk 20.20.1, 21.12.3, 22.10.1, 23.4.1 and Certified Asterisk 20.7-cert11, 22.8-cert3, an authenticated attacker may cause a heap buffer overflow through an out-of-bounds write in the `Codec2` decoder caused by a `floor/ceil sample-count mismatch`. The `codec_codec2` module must be loaded and `Codec2` must be configured on the attacked endpoint. The attacker must pass SIP authentication by username/password or `source IP address matching`, establish a call using `Codec2`, and send carefully crafted `Codec2` audio packets. This issue is fixed in Asterisk 20.20.1, 21.12.3, 22.10.1, 23.4.1 and Certified Asterisk 20.7-cert11, 22.8-cert3.

## Remediation

No remediation reported in collected sources

## Affected products and versions

- asterisk / asterisk: < 20.20.1 (affected); >= 21.0.0-pre1, < 21.12.3 (affected); >= 22.0.0-pre1, < 22.10.1 (affected); >= 23.0.0-pre1, < 23.4.1 (affected). Source: CNA: GitHub_M
- asterisk / certified-asterisk: < 20.7-cert11 (affected); >= 22.8-cert1-pre1, < 22.8-cert3 (affected). Source: CNA: GitHub_M

## Severity and prioritization

- CVSS 4.0: 6 (medium); CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N; source: CNA: GitHub_M

- CISA KEV: No listing in collected sources

- EPSS: 0.65% as of 2026-11-02; percentile 51.16%

- SSVC: exploitation none; automatable no; technical impact partial; source ADP: CISA-ADP

- Weaknesses: CWE-125, CWE-131, CWE-787

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://github.com/asterisk/asterisk/security/advisories/GHSA-qf8j-jp7h-c5hx (CNA: GitHub_M; x_refsource_CONFIRM)

- https://github.com/asterisk/asterisk/commit/02e2d8d51efe1f811f2929224339cb1a35ffc079 (CNA: GitHub_M; x_refsource_MISC)

- https://github.com/asterisk/asterisk/commit/4f5cad0611c67638a0a61cfedbe645045da8dd56 (CNA: GitHub_M; x_refsource_MISC)

- https://github.com/asterisk/asterisk/commit/9b085d48fb66e90a0740ea59e26840421fd07acb (CNA: GitHub_M; x_refsource_MISC)

- https://github.com/asterisk/asterisk/commit/a0bc717b2261f4df7cdecc22b58a5fffbd1aa398 (CNA: GitHub_M; x_refsource_MISC)

- https://github.com/asterisk/asterisk/commit/a2f1cc611f7d0f21faa03e8535009df3041c434c (CNA: GitHub_M; x_refsource_MISC)

- https://github.com/asterisk/asterisk/commit/aa40bc599a8e628859ef1c4fc944261423ceac0d (CNA: GitHub_M; x_refsource_MISC)

- https://github.com/asterisk/asterisk/commit/d4ccfd55ffd7cf6d73a6e5cde347a7464c301006 (CNA: GitHub_M; x_refsource_MISC)

- https://github.com/asterisk/asterisk/releases/tag/20.20.1 (CNA: GitHub_M; x_refsource_MISC)

- https://github.com/asterisk/asterisk/releases/tag/21.12.3 (CNA: GitHub_M; x_refsource_MISC)

- https://github.com/asterisk/asterisk/releases/tag/22.10.1 (CNA: GitHub_M; x_refsource_MISC)

- https://github.com/asterisk/asterisk/releases/tag/23.4.1 (CNA: GitHub_M; x_refsource_MISC)

- https://github.com/asterisk/asterisk/releases/tag/certified-20.7-cert11 (CNA: GitHub_M; x_refsource_MISC)

- https://github.com/asterisk/asterisk/releases/tag/certified-22.8-cert3 (CNA: GitHub_M; x_refsource_MISC)

- https://github.com/asterisk/asterisk/tree/24.0.0-pre1 (CNA: GitHub_M; x_refsource_MISC)

## Provenance

- CNA: GitHub_M: https://www.cve.org/CVERecord?id=CVE-2026-57192; retrieved 2026-11-03; source updated 2026-11-03

- FIRST EPSS: https://api.first.org/data/v1/epss?cve=CVE-2026-57192; retrieved 2026-11-03; source updated Not reported

Revision: 41a9eba57e3a1c39d219c372af838a4443dbac302f9d4fbcfa9aceace32c01b0

Canonical: https://y2.dev/cve/CVE-2026-57192

## Agent and API access

Public CVE pages, Markdown, and JSON are free to read without an account or API key.

- Public catalog: https://y2.dev/cve/index.json. Follow nextCursor with the same search, filters, sort, and limit (1–100). A null cursor marks the end.

- WebMCP: search_cve_disclosures, get_cve_disclosure, get_cve_page_markdown, get_y2_cve_access. Available in compatible browsers.

- Cyber API: https://api.y2.dev/api/v2/cyber/cves and https://api.y2.dev/api/v2/cyber/cves/{cveId}.

- Y2 Pro or Elite: create a workspace API key with the intel:cyber scope and send Authorization: Bearer <Y2_API_KEY>. Setup: https://y2.dev/docs/api/create-key.

- x402: Pay per request without an account or API key. Omit Authorization, read the HTTP 402 PAYMENT-REQUIRED challenge, validate its current requirements, and retry with PAYMENT-SIGNATURE through an authorized payment client. These browser tools never make payments. Guide: https://y2.dev/docs/api/x402.

- OpenAPI: https://y2.dev/api/openapi.yaml. Agent access metadata: https://y2.dev/cve/agent.json.

Collected public records only. Check source status for coverage and freshness.